1. Field of the Invention
This invention relates to an improvement in a process for drying a coated web, such as a drying process during manufacturing a photographic photosensitive material by applying a coating composition onto a metal support and then drying.
2. Description of the Prior Art
Various photographic photosensitive materials and other materials are manufactured by drying a continuous web such as a metal support, a plastic support or a paper support on which one or more coating compositions are applied. This composition is generally produced by dissolving or dispersing prescribed components in an organic solvent. The coated web is dried by blowing hot air or irradiation of infrared light. It is also known that the coated web is dried by the radiant heat from heating plates disposed on the upper side and lower side of the web (Japanese Patent KOKAI No. 60-149871).
Incidentally, in the manufacturing process of photographic photosensitive materials, since it is advantageous to apply the coating composition continuously, strips having a limited length were successively joined and supplied to the applying portion without the interruption of the applying work. However, in the case that the heat capacity of the web was great, it was recognized to generate a temperature difference in the web according to the difference in the thickness (the difference in the heat capacity), since the temperature of the web at the exit of the drying apparatus did not reach an equilibrium with temperature of drying air or the like. Such a difference resulted the difference of dried degree, and affected adversely the quality of the product. Heretofore, in order to decrease the above affect, a sufficient drying equipment was provided, and thereby, the above problem was avoided. Recently, the coating speed has tended to be raised by the requirement to raise productivity. However, since there is a limit to decrease the coating amount and to densify the coating solution, the space to be occupied by the drying apparatus has tend to increase.